Work vehicle compression ignition power system with intake heat exchanger

Abstract

The power system includes a compression ignition engine configured to combust intake gas; an intake arrangement configured to intake charge air; an exhaust arrangement to receive a first portion of the exhaust; an EGR arrangement to receive a second portion of the exhaust as EGR gas; a first mixer to selectively mix a first portion of the EGR gas and the charge air as mixed gas; an intake heat exchanger positioned upstream or downstream of the first mixer and respectively configured to receive one of the intake charge air or the mixed gas such that heat is exchanged with engine coolant; a second mixer positioned downstream of the first mixer and the intake heat exchanger and configured to selectively mix a second portion of the EGR gas and the mixed gas to form the intake gas; and an intake manifold configured to direct the intake gas into the engine.

What is claimed is: 
     
       1. A power system for a work vehicle, comprising:
 a compression ignition engine configured to receive and combust intake gas to generate mechanical power and exhaust; 
 an intake arrangement configured to intake charge air; 
 an exhaust arrangement configured to receive a first portion of the exhaust generated by the compression ignition engine; 
 an EGR (exhaust gas recirculation) arrangement configured to receive a second portion of the exhaust generated by the compression ignition engine as EGR gas; 
 a first mixer configured to selectively receive and mix a first portion of the EGR gas and the charge air as mixed gas; 
 an intake heat exchanger positioned either upstream of the first mixer or downstream of the first mixer and respectively configured to receive one of the intake charge air or the mixed gas such that heat is exchanged between with engine coolant circulating in the intake heat exchanger and the one of the intake charge air or the mixed gas; 
 a second mixer positioned downstream of the first mixer and the intake heat exchanger and configured to selectively receive and mix a second portion of the EGR gas and the mixed gas to form the intake gas; and 
 an intake manifold configured to receive and direct the intake gas from the second mixer into the compression ignition engine for combustion. 
 
     
     
       2. The power system of  claim 1 , wherein the compression ignition engine is configured to operate with a low cetane fuel. 
     
     
       3. The power system of  claim 2 , wherein the compression ignition engine is configured to operate with fuel having a cetane value of less than 40. 
     
     
       4. The power system of  claim 3 , wherein the intake heat exchanger is positioned downstream of the first mixer such that the heat is exchanged between with engine coolant circulating in the intake heat exchanger and the mixed gas. 
     
     
       5. The power system of  claim 4 , wherein, under a first set of conditions, the intake heat exchanger is configured to heat the mixed gas. 
     
     
       6. The power system of  claim 5 , wherein, under a second set of conditions, the intake heat exchanger is configured to cool the mixed gas. 
     
     
       7. The power system of  claim 3 , further comprising:
 a first EGR valve configured to control an amount of the first portion of the EGR gas directed to the first mixer; and 
 a second EGR valve configured to control an amount of the second portion of the EGR gas directed to the second mixer. 
 
     
     
       8. The power system of  claim 7 , further comprising a controller coupled to the first EGR valve and the second EGR valve and configured to control the first EGR valve and the second EGR valve such that the intake gas has a temperature such that, upon compression, the intake gas auto-ignites. 
     
     
       9. The power system of  claim 1 , wherein the intake arrangement includes at least one compressor configured to receive and compress the intake charge air upstream of the first mixer. 
     
     
       10. The power system of  claim 9 , wherein the exhaust arrangement includes at least one turbine driven by the first portion of the exhaust and rotationally coupled to drive the at least one compressor. 
     
     
       11. The power system of  claim 10 , wherein the intake arrangement includes two compressors and the exhaust arrangement includes two turbines that collectively form dual turbochargers. 
     
     
       12. The power system of  claim 11 , wherein the intake arrangement further includes an interstage cooler positioned in between the two compressors to cool the intake charge air. 
     
     
       13. The power system of  claim 1 , further comprising a radiator configured to cool the engine coolant. 
     
     
       14. The power system of  claim 1 , wherein the EGR arrangement further comprises an EGR cooler configured to cool the EGR gas upstream of the first mixer. 
     
     
       15. The power system of  claim 14 , wherein the EGR cooler and the intake heat exchangers are separate heat exchangers. 
     
     
       16. A work vehicle, comprising:
 a chassis; 
 a drive assembly supported on the chassis; and 
 a power system supported on the chassis and configured to power the drive assembly, the power system comprising:
 a compression ignition engine configured to receive and combust intake gas to generate mechanical power and exhaust; 
 an intake arrangement configured to intake charge air; 
 an exhaust arrangement configured to receive a first portion of the exhaust generated by the compression ignition engine; 
 an EGR (exhaust gas recirculation) arrangement configured to receive a second portion of the exhaust generated by the compression ignition engine as EGR gas; 
 a first mixer configured to selectively receive and mix a first portion of the EGR gas and the charge air as mixed gas; 
 an intake heat exchanger positioned either upstream of the first mixer or downstream of the first mixer to respectively configured to receive one of the intake charge air or the mixed gas such that heat is exchanged between with engine coolant circulating in the intake heat exchanger and the one of the intake charge air or the mixed gas; 
 a second mixer positioned downstream of the first mixer and the intake heat exchanger and configured to selectively receive and mix a second portion of the EGR gas and the mixed gas to form the intake gas; and 
 an intake manifold configured to receive and direct the intake gas from the second mixer into the compression ignition engine for combustion. 
 
 
     
     
       17. The work vehicle of  claim 16 , wherein the compression ignition engine is configured to operate with a low cetane fuel. 
     
     
       18. The work vehicle of  claim 17 , wherein the compression ignition engine is configured to operate with fuel having a cetane value of less than 40. 
     
     
       19. The work vehicle of  claim 18 , wherein the intake heat exchanger is positioned downstream of the first mixer such that the heat is exchanged between with engine coolant circulating in the intake heat exchanger and the mixed gas. 
     
     
       20. The work vehicle of  claim 19 ,
 wherein, under a first set of conditions, the intake heat exchanger is configured to heat the mixed gas, and 
 wherein, under a second set of conditions, the intake heat exchanger is configured to cool the mixed gas.